1. Field of the Invention
This invention relates to methods of, and apparatus for, making aperture-defining frame members of the kind comprising a rigid frame-shaped reinforcement embedded in synthetic resinous material.
The invention has been developed in connection with the manufacture of window frames and in particular the type of window frame including an outer frame to be secured to a building and an inner frame pivotally or otherwise movably mounted on the outer frame. In such window frames the outer and inner frames will normally be rectangular. The invention is not limited to the production of such window frames and can be applied to the manufacture of aperture-defining frame members in general. Such frame members may be endless, e.g., rectangular or polygonal, or may be open frame members such as, for example, a door frame which comprises two parallel members with a third member which joins the one ends of the two members while the other ends of the two parallel members are unjoined. The term "aperture-defining frame members" is used herein to include both open and closed frame members.
2. Description of the Prior Art
In making such frame members the synthetic resinous material, i.e., plastics material may be injected into the mould cavity at a pressure in excess of 10,000 p.s.i. so that the pressure in the mould cavity is likely to be at least 5,000 p.s.i. The reinforcement must be held accurately in position in the cavity and must also be held against deflection and distortion.
It has previously been proposed to hold the reinforcement either by four sets of projections lying in two planes, or sets of planes, at right angles or by two sets of projections lying in one plane or a set of parallel planes with metal or plastics chaplets between the reinforcement and the walls of the mould cavity. For example in the former arrangement, considering a reinforcement of square section arranged with its sides vertical and horizontal there may be two sets of projections in vertical planes engaging horizontal surfaces of the reinforcement and two sets of projections in horizontal planes engaging vertical surfaces of the reinforcement. In the latter arrangement there may for example be two sets of projections in vertical planes engaging horizontal surfaces of the reinforcement and the plastics or metal chaplets may be between vertical surfaces of the reinforcement and the sides of the mould cavity.